ALDEHYDE-FUCHSIN FOR PITUITARY CYTOCHEMISTRY

The component of the aldehyde-fuchsin stain which is useful for pituitary staining requires more delicate manipulation than the elastic tissue component. Manufacture of the stain for pituitary purposes may he shortened to 26 hours by subjecting a 0.5% basic fuchsin solution in 70% ethanol, 0.75% paraldehyde and 1.25% HCl to incubation at 37°C. The pH of this solution precludes background staining, allowing aldehyde-fuchsin to be followed by the periodic acid-Schiff routine. Aldehyde fuchsin may be rejuvenated by adding basic fuchsin in alcoholic solution. Oxidation of pituitary tissue allows aldehyde-fuchsin to stain not only thyrotrophs but gonadotrophs as well and accentuates the staining of the hypothalamic hormones and the Golgi bodies. Since some fixatives, such as dichromates, oxidize tissue, assay of the significance of aldehyde-fuchsin staining involves awareness of the influence of the particular fixative employed. Spectrophotometric analysis of young and old aldehyde-fuchsin stains supports the assumption that staining of the pituitary thyrotrophs may involve other constituents of the stain complex than those relied on for elastic tissue visualization.